


Beast

by avacadoo



Category: Voltron: Legendary Defender
Genre: Anal Fingering, Anal Sex, BAMF Lance (Voltron), Bottom Lance (Voltron), Eventual Fluff, Eventual Happy Ending, Face-Sitting, Galra Keith (Voltron), Incubus Lance (Voltron), Keith (Voltron) is a Mess, Keith pretty much wants Lance to step on him lmao, Knotting, M/M, Mating Cycles/In Heat, Rimming, Self-Lubrication, Smitten Keith (Voltron), Smut, Top Keith (Voltron)
Language: English
Status: In-Progress
Published: 2020-01-04
Updated: 2020-01-04
Packaged: 2021-02-27 15:21:47
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 4,802
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22119340
Author URL: https://archiveofourown.org/users/avacadoo/pseuds/avacadoo
Summary: In which Lance is an incubus going through a heat and Keith just wants to do his best to help him out, while also using the situation to his own advantage.
Relationships: Keith/Lance (Voltron)
Comments: 7
Kudos: 218





	Beast

**Author's Note:**

> I wrote this super fast, so there a shit ton of errors! Please tell me if you see an error or inconsistency so I can fix it y'all! Also, this fic was heavily inspired by the song 'Beast' by Mia Martina ft Waka Flocka so I would reccomended listening to it while reading the fanfic.  
> You can listen to it here (just copy the link)
> 
> https://youtu.be/A1f6yEKABJE

At the sound of the airlock doors opening, the team turned to it quickly, hoping that it was Lance that was finally here. They had already been waiting for him for 4 long hours after they realized he left to go somewhere, but didn't tell them where. They refused to go to sleep without waiting for at least 4 hours, and even though they already reached the 4 hour mark, they all agreed to at least wait for 30 more minutes.

It was already 3 in the morning, and Pidge had begun to drift over Hunk's shoulder, and Hunk's eyes were lidded with exhaustion, since had been the one most affected by Lance's sudden disappearance. He was incredibly worried and all the possible outcomes of what could have happened to his best friend were running through his head. Shiro and Allura both were incredibly disappointed as to why Lance didn't tell them where he was going to, they didn't tell them that he was leaving the castle at all in fact. Keith was incredibly angry that Lance wouldn't at least tell him where he was going, but he was also worried nonetheless. Why would Lance not feel comfortable to tell Keith, one of his best friends where he was going? And what kind of shady place was Lance going to that he couldn't even tell Keith where he was heading off to? 

Lance sauntered into the castle all disheveled and messed up. He was slugged over in horrible posture, and he was limping slightly. there was a sheen of sweat over his face, like he had been exercising before he arrived. His brown locks were all pointed in different directions, almost as if he just came out of bed. His paladin uniform had begun to slip off one of his shoulders due to how poorly it was fastened in, revealing a dark hickey on his shoulder and one on his collarbone as well. His normally soft lips were glazed over and puffed up, a small bite on the corner of his bottom lip. He also had a red streak on the side of his mouth, a streak that looked an awful lot like blood. His lips were red from irritation, almost as if someone had been kissing him with very little regard before he arrived at the castle. His normally ocean blue eyes looked glazed over and lidded, like he was still struggling to believe that we were in the castle. Not to mention they didn't even appear blue, for a moment they looked as if they were a glowly red color, but Keith might have imagined it. He looked so lustful, so different. He looked ethereal. He looked...hot.

Keith shook that thought out of his head. This was Lance he was talking about, obnoxious and flirty Lance, the Lance that never takes anything seriously, the Lance that Keith thought was cute in his own way, the Lance he fell for. Not this sex demon replica of Lance, that was practically oozing with appeal. He started at Lance in awe, only for him to catch Keith looking at him, giving him a wink which made Keith look away in embarrassment and anger. 

Lance just smirked at him. 

Allura gasped at the sight of Lance. 

"Where have you been?" She questioned angrily, getting up from the couch followed by Shiro and Keith, all glaring at Lance. 

Lance's eyes burned into them, giving off a strange vibe. 

"Why are you guys up?" He rasped, his voice low and deep, a heavy contrast to his normally high pitched tone. 

"You've been gone for hours now! Did you think we would just go to sleep peacefully knowing you might be outside dead? But you have the nerve to come in here looking like you just got laid?" Keith fumed, glaring at Lance right back with the same level of intensity. Allura put her hand on his shoulder as if to calm down, but that only made Keith angrier. 

Lance smirked again, his tongue coming out to lick at the blood on the corner of his mouth. Something was off about the sight, Keith noticed. Lance's tongue was far too long to be considered normal, and this time Keith was absolutely sure that Lance's eyes were red. There was no mistaking that foreign glint in his eyes, that was what happened before Lance was about to do something drastic. 

"Don't worry about it. It's nothing new." Lance snapped, rolling his eyes as if this was all just an exaggeration, as if it was normal for Lance to go out at night and leave the rest of the team worried. 

This was when Keith was definitely sure something was wrong with Lance. His nails seemed to be far too long, rather than the short, blunt nails that he usually had. Not to mention that there was a black spreading on them, a black that was definitely not the clear acrylic nail polish Lance would usually use on them when he wanted to treat himself to something nice. Something was off about him. Something was very off. 

He could hear Allura arguing with Lance in the back of his mind, but all he could think about was how he had never seen Lance in his room at night at all. He could sense that something bad was going to happen, he could just feel that something wasn't right here, something wasn't right with Lance. All that was running through his head was that wasn't the Lance they knew and loved, it wasn't their Lance. This was a completely different person here in front of them, some demon. 

Lance's eyes darted to Keith as if he knew what he was thinking at this very moment. Lance's tongue was sticking out almost as if he was getting ready for a meal. 

"If it makes you feel any better, I really wished you hadn't been waiting for me." Lance apologized cryptically, stepping away from Allura slowly, his movements fast and sudden, but precise. 

The team was all now fully paying attention, Hunk and Pidge waking up from their mini nap to gaze at Lance curiously. Lance had captured all their attention, and Keith wasn't sure if that was good or not.

"No running now, ok?" Lance snickered at his own joke, before breathing in and out slowly if he was preparing for what's to come next. 

Then everything started so fast, too fast. Lance closed his eyes slowly before opening them, revealing a bright, blinding ruby red color. Before the team could react, Lance sighed and suddenly there were these two, demon like horns rising from stop of his head. He wasn't finished yet, though. His hands turned coal black, fading into his normal caramel skin tone only at his elbows. Then, thick claws at least 5 inches long rose from his fingertips, and Lance giggled in excitement, giddy over what's to come next. The white of his eyes had turned to black in seconds, receiving a collective gasp from the team. Then, his canines slowly grew to be about a half an inch longer, and when he licked his lips to feel them, his tongue grew to be twice the size it usually was.

"This part will take a second." Lance groaned out in frustration, face contouring in what seemed to be..pleasure. Suddenly, two matching wings burst out of his back, forcing his paladin uniform to tear in order to accommodate his wings. When his paladin uniform fell to the ground, a tight black leather crop top was revealed, it barely covered his chest, reaching down to stop a few inches above his belly button. Not to mention he had these matching booty shorts to match that stopped just below his ass cheeks, and God, Keith wasn't religious, but he would worship the ground those toned legs walked on. To top everything off he had these high heeled boots that were paired with thigh high red lace socks. In addition to all that, he also had chains wrapping around the entirety of his body almost like a snake, curling in between his legs and around his neck. He was Keith's fucking nightmare. After taking one look at the walking sex dream I'm front of him, Keith knew he was screwed. He was so fucking screwed.

"Ohmygod...that feels so much better." Lance moaned in a mixture of pleasure and relief, adjusting to his new body by flapping his wings a couple of times, letting his body lift into the air, gazing down at his teammates almost as if he was wondering which one he would devour first. 

The whole team was speechless, all of them looking down, or rather, up, at Lance blankly, still frozen in shock, believing that their eyes must be deceiving, because there's no way this was Lance. This was not the awkward but adorable teenage boy that was flirting with Allura just a day ago, this was the hot demon that was practically oozing with confidence. 

Allura was the first one to speak up.

"Lance...what are you?" She asked hesitantly, blushing after seeing Lance bend over in the air slightly, revealing a peek of lace red panties hidden snug unter his shorts. Keith was absolutely sure that Lance did it on purpose, considering that he turned around to wink at Keith, almost as if he could feel his stares.

"I have many names that people recognize me by. Demon, devil, whatever. But if we're being technical here, I'm a full incubus. Lance is a full human. So I guess that makes us half incubus? I am the other side of Lance, the side he has no recollection of when morn arrives. To prevent Lance from turning full incubus until he's ready, I have to feed every night." Other Lance explained, swirling around Keith in pure delight, seeming to take a liking to being around the galra male, squirming when he got too close to him, his face turning pink and red pupils dilating.

"I can see why Lance takes a liking to you." Other Lance moaned in pleasure, licking up the side of Keith's cheek, making him shudder and wipe his face 

Allura tilted her head. 

"And what exactly is an "incubus"? And what can we call you if you aren't the same person as Lance?" She asked in genuine curiosity of what Lance's species was, causing Lance to cover his mouth sniggering, floating higher in the air with each laugh. Keith would have found it cute if not for the circumstances they were in right now. 

Shiro shoved his blushing face into his hands after realizing no one else was going to explain it, even other Lance. He was far too busy ogling at Keith. 

"It's a demon that feeds off of sexual pleasure." He muttered, avoiding other Lance's pleased gaze, looking proud in the fact that Shiro knew what he was. 

Alluras face turned red in shock, whispering a quiet "oh" under her breath. 

"As to that other question, I guess you could call me Blue, considering it has always been our favorite color." Blue smiled genuinely.

"Will you ever leave permanently? Like can Lance ever take you over forever?" Keith questioned hesitantly, stepping away from Blue. He remembered reading on some paranormal website that incubus's can be controlled. Would it be the same for Lance?

"Yes. As soon as Lance becomes of age at 18 years old, he'll get a heat. It's a super painful, week long event that will make Lance a half incubus. I will become a part of him, once and for all. He won't be like me though. This will basically just make him the Lance you know and love, but with heavy sexual cravings. Since he was born in his human form he'll feel more comfortable in it so you guys won't have an incubus around you 24/7, but will occasionally switch over in his incubus form in heats and when he feels threatened. He will still feel love and affection for everyone, nothing will be wrong with him at all, he'll be the exact same teammate you normally have." Blue answered, taking a step closer to Keith again. 

"Wait Lance's birthday? His 18th birthday is on the 28th though? You mean the heat thingy will start tomorrow?" Pidge questioned in shock, looking at the calendar on the ship to see if she was mistaken. She wasn't. The team had all been preparing for Lance's birthday for a week now, but now they have to prepare for something completely different.

"Why were you even out?" Pidge asked in a half statement half question, glancing up at Blue with a confused expression on her face.

Blue sighed at that. 

"And I thought you were supposed to be the smart one here. If I don't feed for more than a couple of days, I grow weak and become full incubus, meaning you'll never see your Lance again. So in order to prevent that from happening, I go to an alien brothel every couple nights and choose a random alien to feed off of. I never do much, mostly oral sex and makeout sessions. It would be too obvious if I had sex with someone, because Lance would definitely realize in the morning." Blue explained idly, messing with his chains. 

Keith fumed at that. How often had Lance.. Blue.. been giving out complimentary blow jobs to any alien that has a dick? Anything could happen to him, and that worried the hell out of Keith. 

"You just said "every couple nights" Lan- Blue. How often have you been doing this?" Hunk asked quietly, worried as to what Blue's answer may be. 

Blue stiffened at that, looking at Hunk in a way Keith couldn't differentiate. He almost looked...ashamed. 

"This isn't "50 questions" here, alright?" Blue smiled sweetly, giving Hunk the same look he gave to him just seconds ago. 

Blue's teeth gleamed at Keith. 

"Now here's the thing, I'm going to go to sleep now, and your Lance will wake up in intense and excruciating pain. He won't be the only one that's uncomfortable though. If he doesn't have a partner, he'll release pheromones so strong that will urge you guys to go to him, and eventually you will sleep with him. It is inevitable." Blue warned. 

"So, who wants to be the partner of the blue paladin?" 

The team all looked at Keith unanimously. As much as they want to be there for Lance, they couldn't do it to Keith in their right mind knowing how he feels about him. They couldn't do that to Lance, either. They knew how Lance felt about Keith as well, Lance was always trying to get his attention no matter what the circumstance. He would be the most comfortable with Keith at his bedside, not any other. 

"I'll do it." Keith said, giving the team a nod of appreciation, glad that they all let him volunteer with no arguments. It meant a lot to him, even if it didn't look like it did. 

Blue smirked at Keith for the umpteenth time, but then it turned into a smile at him.

"I don't think Lance would want it any other way." He confessed, which seemed to be honest, Keith noted.

"Well good night forever. By the time you see me tomorrow, I'll already be a part of Lance." Blue said cooly, walking away from the team and to his- Lance's room.

The team watched as Blue walked off, his tail, which they hadn't even noticed, swishing behind him gracefully. 

Shiro looked at the team seriously. 

"I know that this is a lot to take in right now, but we have to stay strong. For Lance. It's a week long ceremony, right? We have to help them prepare, we have to get Lance's room ready." directed Shiro, already starting to give orders. 

"Hunk, you prepare sustainable food and water that they can have in the room. Pidge, you gather fresh clothes and sheets for when they're finished with the, um, heat. Allura, Coran and I will help you out as well. Once we are finished, we'll leave to the Olkarion planet for a week, or until the heat is over so we can keep up with space affairs and give Keith and Lance some privacy. Coran has already contacted them, and they said that they had rooms in the castle we could stay in for as long as we need." Shiro announced, giving the team a nod. 

"Got it!" 

"On my way!"

"Of course." 

Keith smiled at his team, and how willing they were to help out. 

Shiro the looked at Keith. 

"Keith, right now all that's important for you is to get some rest. God knows how much you'll get of it tomorrow." Shiro chuckled knowingly, earning a jab to the stomach from Keith, causing Shiro to wince and groan out an "ow".

"You deserved that." Keith deadpanned, before leaning in to give his brother a hug. 

"Really though, thanks Shiro. I appreciate it." Keith smiled before leaning away. 

"Anytime. Good night, man." Shiro grinned, pushing Keith in the direction of his room.

Keith took a quick shower before going to bed, drifting off to the thought of Lance.

\-----------------------------------------------------------

Lance moaned in alert, waking up to soaked boxers and a hard on. His whole body felt hot, and everything was so intense and painful, he just wanted to curl up in a ball and pass out. 

He didn't even have time to wipe the sleep from his eyes and think of his birthday before he jolted in a mixture of arousal and hurt. 

He could feel something weird growing out of his head, but when he reached out to feel it, he realized that they were horns. Horns were growing out of head. That wasn't all, he could feel something prick the inside of mouth, sensing that his canines were longer and sharper. Then all of a sudden, he felt a bursting, excruciating pain in his back, causing him to scream out in agony until it finally stopped, feeling a new sensation. He reached out and felt wings. Fucking wings. What the hell was going on?

He waited for God knows how long, whimpering in pain as his body continued to transform. By the end of it, he was left with a tail, wings, horns, and fucking claws. Worst fucking birthday ever. 

"What..what's going on?" He muttered to himself, trying to get out of his bed to ask someone for help, only to fall to the ground on weak legs with a 'thud'. 

He couldn't do anything but whimper in pain and shove his face into the floor with his ass up sticking the air, arousal already running its course through his veins. He grabbed a pillow from his bed needily, trying to hump on it to relieve his aching need, but it didn't help him at all, so he discarded it quickly. He could feel something wet and slick seeping through his boxers and trickling down his thighs, so he just decided to remove them completely for better access to his manhood. . 

He wrapped his hands around his cock, pumping it slowly to try and relieve his neediness, but it wasn't enough. He needed something else, he needed something different. He let one of his hands snake down to his ass gently, fingers reaching for his entrance desperately, only to feel how hot and wet he was. He couldn't think about how odd this was, couldn't think about waking everyone up, all he could think about was how he needed relief. Right now. 

He moaned the second he dragged his finger down his perineum, trailing his finger down to the sensitive ring of muscle and rubbing with two fingers now. He cried the first name that came to his mind. 

"Keith." He breathed out, one hand occupied by pressing a fingertip into his ass, his other hand wrapped around his manhood, giving it slow and sensual strokes. 

He wanted Keith here right now. He knows Keith would be so good to him, driving his fingers into Lance aggressively, his thick and heavy fingers reaching places in Lance this his dainty hands never could. He mewled at the thought of Keith fingering him, putting one finger into Lance and letting Lance rock back into them. He would be so sweet to Lance despite their situation, he would praise Lance, calling him a "good boy" or "you're doing great for me". He could already imagine Keith's husky voice whispering sweet nothings into Lance's ear.

Lance teased his hole frantically, rubbing the ring of muscle wantonly and occasionally plunging the tip of his finger in and out of his entrance. He had fingered himself before, but something about doing it now fr so different, and so damn good. His cock was aching with need, dripping onto the floor along with the slick that had accumulated. Lance eagerly put one finger inside of his ass, putting it in halfway before shoving the finger in eagerly.

"Hah..." He moaned, rocking his ass back onto he digit, trying to chase the pleasure and to make the finger reach his prostate. He knows that he wouldn't be able to do it on his own, but maybe if Keith was here he would help him out. Keith would be so good to him shoving his rough callused fingers into Lance, he would probably put in his entire hand if Lance wanted it.

Lance mewled at the thought of just that. Lance hesitantly shoved two fingers into his desperate hole, his body beckoning them in eagerly. Slick was practically pouring down his thighs now, falling onto the floor slowly. He twisted the fingers in his ass and grazed his prostate ever so slightly, having no choice other than to shove his face into his elbow to prevent a shriek

Or would it be different? Would he edge Lance to the point of tears, never letting him get what he so badly wants? 

A door opened, but Lance didn't even turn his head, just continued rocking back onto his finger, moaning Keith's name wantonly, like a bitch in heat. 

Keith's eyes dilated at the sight. Lance's face was down on the floor, ass up in the air, full of his own fingers but still moaning Keith's name desperately. Keith could feel a strange possessive urge inside of him, the sight of Lance on all fours and begging for Keith like a whore was doing something to Keith. He knew it was probably his galra side talking, but right now Keith wanted to take Lance somewhere isolated and lock him up so that he was the only one able to see him. So that he was all Keith's. No one else's but his. 

At first sight of Lance, Keith wanted nothing more than to shove those fingers away and shove his dick in him, but he had more self control than that. He wanted to drive Lance insane, so insane that he won't even be able to remember his own name by the time Keith is finished with him. He won't be able to walk without Keith's help. Just the thought of it made Keith hard, the thought that Lance could be so vulnerable and only Keith would be able to hell him, he wouldn't be able to do anything without Keith helping him. 

Keith walked up to Lance, picking him up with ease and dropping him down on the bed with ease, towering over Lance, looking down at him with hia eyes lidded with desire. 

"K-Keith?" Lance grunted, looking up at the shorter but more muscular boy in shock, questioning why he was here in Lance's room. 

"I know you're confused Lance, I'll explain everything later, but first let me take care of you." Keith groaned out before smashing their lips together. 

Lance moaned as Keith's tongue fought with his, before separating from Lance with only a line of spit connecting them.

Before Lance could even say anything, Keith attacked his neck, biting at his nape harshly, drawing blood from the spot, earning a surprised jolt from Lance. He then licked at the spot apologetically, cleaning the blood off with his tongue before leaving it with a kiss. 

"Y-You'll leave marks-" Lance whines, trying to lean away from Keith's touch. 

Keith did nothing but hold Lance's hands above his head. 

"Good." He rasped, giving Lance no warning before flipping him over roughly, shoving his face into the pillow roughly, earning a shocked shriek from the Cuban boy, whose face was red from pleasure.

"Ass up." Keith ordered, grabbing Lances hips with no remorse and forcing them up aggressively, making his shaky Lance's stand up. 

"Keith please I need-" Lance mewled as another wave of pleasure racked through him, making his cock even harder, and making more slick run down his thighs, which didn't go unnoticed by Keith. 

"I know babe. Just let me clean you up, you're a mess right now." Keith grunted, and before Lance could ask what he mean, Keith was spreading Lance's legs open, licking the slick that was dripping down his thighs. His tongue went up Lance's upper thigh, before excitedly stopping at his ass. 

"You taste so damn good." Keith cursed, continuing on with actions, making Lance impossibly harder with each touch. 

Lance could do nothing but hold onto his bed sheets tightly and moan. 

Then, without a warning, Keith took his hands and spread Lance's cheeks apart and without a thought, licked up his perniuem eagerly, his hot breath like fire over Lance's skin.

He didn't stop there though. He leaned away from Lance's ass for a split second, only to go back in and thrust his tongue into Lance's hole. He tongued at Lance's rim almost professionally, making Lance's legs go weak under all the pleasure. 

"Please- please don't stop-" Lance begged, sobbing with pleasure as he let his body take over, thrusting himself back onto Keith's tongue to try and chase the pleasure. Keith continued on with his actions, letting his tongue leave Lance's hole for a second only for it to lap at his hole, the flat of his tongue bringing indescribable pleasure. 

"You love this don't you? You're so cute likes this, all riled up to have your ass filled." Keith cooed, continuing to thrust his tongue in and out of Lance, making him so needy and whiny. 

"I-I'm gonna come-" Lance shrieked, trying to reach for his dick to finish himself off quickly, only for Keith to stop him, holding both of Lances arms back with just one of his strong hands. 

"Let's see if you can come only from your ass today. You were about to do it before I came in, so let's try it now.' Keith smirked, letting go of Lance's arms to watch as Lance fisted the sheets in indescribable frustration, letting his hips thrust down onto Keith's face, trying to reach his orgasm desperately, his long black tail waving in front of Keith's face. And who was he to resist a perfectly good opportunity to make Lance fall apart even more? He let one hand wrap around Lance's tail, pumping it to the same place as his tongue, causing Lance to straight up scream. At the sight of Lance losing himself and basically begging for Keith, he decided to give Lance a break from all the torture. He quickly shoved a finger along side his tongue, making Lance cry in pleasure, coming immediately from just that, Keith's name on his lips as his release painted his stomach and sheets.

Keith continued to finger him however, trying to get Lance accustomed for what's to come next. This time his touches were more gentle, trying to let come down from his previous orgasm. Lance had fingered himself earlier, but it wasn't enough for Keith's galra dick. He needed more preparation. Besides, Keith wanted to make Lance enjoy this, considering the amount of pain he was in right now. Keith just wanted to take care of him now, making sure that Lance can feel good out of this despite the circumstances. 

He would do anything for that to happen. He glanced at Lance to see how he was doing, his dick growing incredibly harder at the sight.

Lance's eyes were glazed over from the aftershock, his face red with need, tears dripping down his face and onto the bed. He looked so beautiful, that Keith could resist leaning in close and giving him a kiss on his sweaty temple, make Lance shudder with sensitivity.

"Good boy." Keith couldn't help but grin at his Lance. So good for him. Only for him. 

Now that the foreplay was all finished, it was time for the real part to begin.

**Author's Note:**

> I'll upload chapter 2 as soon as possible! Please leave kudos and comments if you liked it! 😊


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